The U.S. Geological Survey has released a preliminary earthquake report of a 2.7 magnitude earthquake last night.  According to the preliminary report, the earthquake hit around 10 PM about 9 miles east-southeast of Ina and 17 miles south-southeast of Mount Vernon.  The quake was in the Illinois Basin Ozark dome, a large region that borders the much more seismically active New Madrid seismic zone on the seismic zone’s north and west.  Moderately frequent earthquakes occur at irregular intervals throughout the region.  The largest historical earthquake in the region was at magnitude 5.4 and damaged southern Illinois in 1968.  Moderately damaging earthquakes strike somewhere in the region each decade or two, and smaller earthquakes are felt about once or twice a year.